Evaluation of the classification and diagnosis of Sz

• lack of inter-rater reliability

  schizophrenia has been shown to have poor inter-rater reliability when it comes to diagnosing it

  Whaley (2001) found inter-rater reliability correlations in the diagnosis of schizophrenia as low as 0.11 (a score of 1 indicates perfect inter-rater agreement)

  Rosenhan (1973) being sane in insane places:

  • 'normal' people presented themselves to psychiatric hospitals in the US claiming they heard unfamiliar voice in their head saying the words 'empty', 'hollow' and 'thud'
  • they were all diagnosed as having schizophrenia and admitted
  • throughout their stay, none of the staff recognised that they were not actually displaying symptoms of schizophrenia
  • highlights the unreliability of diagnosis
• cultural differences (reliability)

  research suggests that there is a significant variation between countries when it comes to diagnosing schizophrenia

  Copeland (1971)- gave US and British psychiatrists a description of a patient. 69% of the US psychiatrists diagnosed schizophrenia, but only 2% of the British ones gave the same diagnosis

  hearing voices is more acceptable in African cultures because of cultural beliefs in communication with ancestors. when reported to a psychiatrist from a different culture these experiences are likely to be seen as irrational = more likely to be diagnosed with schizophrenia
• gender bias (validity)

  this is said to occur when accuracy of diagnosis is dependent of the gender of an individual. it has been found that males are more likely to be diagnosed than females-> they appear to typically function better than men, being more likely to work and have good family relationships. this high functioning may explain why some women have not been diagnosed with schizophrenia where men with similar symptoms might have been

  Loring and Powell (1988)- selected 290 male and female psychiatrists to read two case studies of patients' behaviour and asked to offer their judgement. when the patients were described as 'males', 56% of the psychiatrists gave a diagnosis of schizophrenia, whereas when described as 'female', only 20% were given a diagnosis
• symptom overlap (validity)

  there is overlap between the symptoms of schizophrenia and other conditions

  both schizophrenia and bipolar disorder involve positive symptoms like delusions and negative symptoms like avolition. this questions the validity of the diagnosis of schizophrenia

  under ICD a patient might be diagnosed as a schizophrenic; however, many of the same patients would receive a diagnosis of bipolar disorder according to DSM criteria
• co-morbidity (validity)

  co-morbidities are common among patients with schizophrenia and this brings into question the extent to which they are separate disorders and not just a single condition (classification of schizophrenia)

  Buckley et al. (2009)- around half of patients with a diagnosis of schizophrenia also have a diagnosis of depression or substance abuse, or OCD. in terms of classification, it may be that, if very severe depression looks a lot like schizophrenia and vice versa, then they might be better seen as a single condition